Method and Apparatus for Updating Sub-Pictures in a Bi-Stable Electronic Reading Device

• US 20070247406A1
• Filed: 08/24/2004
• Published: 10/25/2007
• Est. Priority Date: 08/27/2003
• Status: Abandoned Application

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Zhou, Guofu, Van De Kamer, Jan
• Application Number:
  US10/569,715
• Publication Number:
  US 20070247406A1
• Time in Patent Office: Days
• US Class Current: 345/89
• CPC Class Codes: G09G 2310/04 Partial updating of the display screen
• CPC Class Codes: G09G 2320/02 Improving the quality of display appearance
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• CPC Class Codes: G09G 2320/066 for control of contrast
• CPC Class Codes: G09G 2340/12 Overlay of images, i.e. displayed pixel being the result of switching between the corresponding input pixels
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 3/2044 using dithering
• CPC Class Codes: G09G 3/344 based on particles moving in a fluid or in a gas, e.g. electrophoretic devices electrophoretic devices per se G02F1/167
• CPC Class Codes: G09G 5/02 characterised by the way in which colour is displayed details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 5/14 Display of multiple viewports
• CPC Class Codes: G09G 5/40 characterised by the way in which both a pattern determined by character code and another pattern are displayed simultaneously, or either pattern is displayed selectively, e.g. with character code memory and APA, i.e. all-points-addressable, memory

Abstract

Image quality is improved in an electronic reading device (300, 400), such as an electronic book using a bi-stable electrophoretic display, by determining a position to display a sub-picture (900) over a background picture (800, 810) so that like colors do not overlap. This avoids having a noticeable contrast between the color of the background picture, which may have faded since the background was displayed, and the color of the sub-picture. In another embodiment, a transition region (1310, 1320) is provided between the sub-picture (1350) and the background picture (1300) using an intermediate color, or a dithered or greyscale pattern. The background picture and sub-picture may include text and/or images.

Claims

1. A method for displaying a sub-picture over a background picture on an electronic reading device, the method comprising:

determining a visual characteristic of at least a portion of the background picture (800, 810);

determining a visual characteristic of at least a portion of the sub-picture (900); and

determining a position for displaying the sub-picture (900) so that the at least a portion of the background picture (800, 810) and the at least a portion of the sub-picture (900) are separated when the visual characteristics thereof differ by less than a threshold difference.

2. The method of claim 1, wherein:

the visual characteristics comprise color levels.

3. The method of claim 1, wherein:

the visual characteristics comprise greyscale levels.

4. The method of claim 1, wherein:

the at least a portion of the background picture comprises information that is associated with information of the at least a portion of the sub-picture.

5. The method of claim 1, wherein:

determining the position for displaying the sub-picture comprises determining visual characteristics of different regions (1110) of the background picture until at least one of the regions is located whose visual characteristic differs from the visual characteristic of the at least a portion of the sub-picture by more than the threshold difference.

6. A display comprising:

at least one picture element (2) disposed on a display panel (1);

a control (100) comprising an addressing circuit (105) electrically connected to apply differences in electrical potential to the at least one picture element (2);

wherein the control (100) further comprises a computer program of instructions to cause the control (100) to determine a visual characteristic of at least a portion of a background picture (800, 810) and a visual characteristic of at least a portion of a sub-picture (900), and to determine a position for displaying the sub-picture (900) on the display panel (1) to separate the at least a portion of the background picture (800, 810) and the at least a portion of the sub-picture (900) when the visual characteristic thereof differ by less than a threshold difference; and

the control (100) being configured to cause the addressing circuit (105) to apply one or more of said differences in electrical potential to the at least one picture element (2) to display the sub-picture (900) in the determined position.

7. The display of claim 6, further comprising:

a memory (120) storing data indicating the visual characteristic of the at least a portion of the background picture;

wherein the control (100) further determines the position for displaying the sub-picture responsive to the data stored in the memory.

8. The display of claim 6, wherein the visual characteristics comprise color levels.

9. The display of claim 6, wherein the visual characteristics comprise greyscale levels.

10. The display of claim 6, wherein the at least one picture element (2) comprises an electrophoretic display.

11. An electronic reading device comprising the display of claim 6.

12. A sign comprising the display of claim 6.

13. The sign of claim 12 wherein the sub-picture (900) comprises a message or image which changes rapidly.

14. A method for displaying a sub-picture (1350) over a background picture (1300) on an electronic reading device, the method comprising:

determining a visual characteristic of at least a portion of the background picture (1300);

determining a visual characteristic of at least a portion of the sub-picture (1350); and

displaying the at least a portion of the sub-picture over the at least a portion of the background picture with a transition region (1310, 1320) therebetween in accordance with the visual characteristics thereof.

15. The method of claim 14, wherein:

the transition region has a visual characteristic that is between the visual characteristic of the at least a portion of the background picture and the visual characteristic of the at least a portion of the sub-picture.

16. The method of claim 14, further comprising:

estimating the visual characteristic of the at least a portion of the background picture.

17. The method of claim 14, further comprising:

measuring the visual characteristic of the at least a portion of the background picture.

18. The method of claim 14, wherein the transition region comprises one of a dithered and grey scaled pattern.

19. The method of claim 14, wherein the visual characteristics comprise at least one of color levels and greyscale levels.

20. The method of claim 14, wherein:

the at least a portion of the sub-picture is displayed over the at least a portion of the background picture when the visual characteristic of the at least a portion of the background picture differs from the visual characteristic of the at least a portion of the sub-picture region by less than a threshold difference.

21. A display comprising:

an array of picture elements (2) disposed on a display panel (1);

a control (100) comprising an addressing circuit (105) electrically connected to apply differences in electrical potential to the picture elements (2); and

wherein the control (100) further comprises a computer program configured to cause the control (100) to determine a visual characteristic of at least a portion of a background picture (1300) and a visual characteristic of at least a portion of a sub-picture (1350), and to determine a transition region between the at least a portion of the background picture (1300) and the at least a portion of the sub-picture (1350) according to the visual characteristics thereof, the control (100) being configured to cause the addressing circuit (105) to apply a set of said differences in electrical potential to a portion of the picture elements (2) to display the sub-picture (1350) with the determined transition region (1310, 1320).

22. An electronic reading device comprising the display of claim 21.

23. A sign comprising the display of claim 21.

24. The sign of claim 23 wherein the sub-picture (1350) comprises a message or image which changes rapidly.

25. A computer program product for displaying a sub-picture over a background picture on a bi-stable display, the computer program product comprising:

computer code devices configured to cause a computer to determine a visual characteristic of at least a portion of a background picture (1300) and a visual characteristic of at least a portion of a sub-picture (1350), and to display the at least a portion of the sub-picture (1350) over the at least a portion of the background picture (1300) in a position determined in accordance with the visual characteristics thereof or with a transition region (1310, 1320) between the at least a portion of the sub-picture (1350) over the at least a portion of the background picture (1300) determined in accordance with the visual characteristics thereof.